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Need advice on building AR15 Lower

charliebrown1999

Sergeant of the Hide
Minuteman
Jul 25, 2018
253
47
I am about to click the button to purchase an Aero Precision M4E1 20" Wylde 223 SS fluted bbl complete upper. I will also purchase their BCG. My question is will that upper "run" with their M4E1 lower with rifle buffer and spring and Magpul MOE rifle stock??? The upper has a rifle length gas system. I thought matching rifle length gas system with rifle length gas system. However I am a newbie with AR15 builds.
 
When you say "Magpul MOE rifle stock", do you mean this one?
1566526080557.png


Or this one?

1566526114785.png


Either way, your rifle-length upper will work just fine with a carbine or a rifle lower, but you shouldn't use a rifle-length buffer/spring in a carbine-length tube. The rifle ones are longer and the bolt may not cycle or lock back 100% correctly. Like @Evolution 9 said, you can use a rifle-length upper on a carbine lower just fine; the Diemaco/Colt Canada C7A2 comes from the factory like that. On the other hand, using a carbine upper with a fixed-stock rifle lower like on my own AR works well too and having a solid stock is more comfortable imo.